USB: serial: omninet: fix memory corruption with small endpoint

USB: serial: omninet: fix memory corruption with small endpoint

Make sure that the bulk-out buffers are at least as large as the
hardcoded transfer size to avoid user-controlled slab corruption should
a malicious device report a smaller endpoint max packet size than
expected.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>